Dribble gate



y25, 1954 M. J. BELL 2,679,335

DRIBBLE GATE Filed Feb. 15 1951 2 Sheets-Sheet l /n venfor M///ar0 JBe// Af fornex y 5, 1954 M. J. BELL 2,679,335

DRIBBLE GATE Filed Feb. 15, 1951 2 Sheets-Sheet 2 /n ven for M///ar0 JBe// Patented May 25, 1954 DRIBBLE GATE Millard J. Bell, Grand Rapids,Mich., assignor to Newaygo Engineering Company, Newaygo, Mich., acorporation of Michigan Application February 15, 1951, Serial No.211,162

4 Claims. 1

Thi invention relates to dispensers for foundry molding sand and moreparticularly to an auxiliary gate construction for catching sand whichmay work its way past the closed primary sand gate of a chute or hopper.

In the handling of relatively finely divided materials such as foundrymolding sand, it is customary practice to provide a supply of sand in ahopper from which the sand is withdrawn through a chute or spout. Theflow of sand is normally regulated by a pivoted gate having the shape ofa segment. The hopper is normally positioned above the mold pattern andthe mold is made directly beneath the spout or chute. Often the samehopper is provided with more than one discharge outlet, whereby it mayservice at least two molding stations. The conventional gates employedto control the flow of sand, even though carefully constructed,frequently permit small quantities of sand to leak past them where theleading edge of the gate contacts the lips of the chute. The sand,normally, will not dribble unless the hopper and chute are subjected tovibration. The operation of one of the sand gates vibrates the entirehopper structure sufliciently to cause sand to dribble past the othergate which may at that time be closed. If the mold has: just been drawnin the mold making station immediately below the closed gate, when thishappens, this dribble of sand will ruin the mold. It is the object of myinvention to prevent this difficulty.

Although dribble gates or catchers designed to catch and hold thisdribble of sand as it leaks past the primary gate have been known formany years, these gates have not been satisfactory. The problem has beenthe necessity of removing the dribble catcher from beneath the primarygate substantially instantaneously as the primary gate starts to open.Unless the dribble catcher is removed almost immediately, thedownrushing body of sand, released by the opening primary gate, will becaused to deflect, causing maldistribution of the sand in the flaskbelow and frequent spilling. At the same time, the dribble gate must beso constructed that it will empty the will be displaced substantiallyinstantaneously as the primary sand gate starts to open, whereby it doesnot interfere with the stream of sand released from the hopper or chute.

It is a further object of my invention to provide a dribble gate whichis effective in catching and holding any sand which may dribble past theprimary gate when the primary sand gate is closed.

It is an additional object of my invention to of a sand chute equippedwith my dribble gate with both the primary gate and the dribble gate inclosed position.

Figure 3 is a fragmentary, side, elevation view of a sand chute equippedwith my dribble gate showing the primary gate as it starts to open.

Figure 4 is a fragmentary, side, elevation view of a sand chute equippedwith my dribble gate showing the dribble gate in fully opened positionand the primary gate in partially opened position.

Figure 5 is a. fragmentary, sectional view taken along the plane of VVof Figure 1.

In executing the objects and purposes of my invention, I have provided atrough or dribble gate pivotally suspended below the end of the primarysand gate where the primary sand gate closes against the sand chute. Acam having a notch or shoulder is mounted on the primary sand which hasaccumulated in it at the same time the primary gate is opened.

It is, therefore, a primary object of my invention to provide a dribblegate and catcher which sand gate. A pin is mounted on the dribble gatefor engaging the notch and cam. The relationship of the notch to the pinis such that as soon as the primary gate starts to withdraw from itsclosed position the one wall of the notch will force the pin to rotatethe dribble gate rapidly into its fully open position. The cam willretain the dribble gate in open position until the primary sand gate isagain almost fully closed.

In the following description, I describe my invention as applicable tofoundry equipment. This is for convenience only and is not to beconsidered in any way as a limitation. The handling of foundry sand isits primary purpose, but it will be understood that this is only onepossible use which could be made of my invention. My invention isequally usable in almost any situation in which a pivoted gate is usedto control the flow of a finely divided, solid material, where it isdesired to collect the leakage of material around the primary controlgate.

In the following description the terms upwardly and downwardly arefrequently used and. are to be taken as meaning upwardly the directionshown in each of the views and downwardly away therefrom. The terms upper and lower are to be considered as synony mous with upwardly anddownwardly; respec tively.

Referring now to the drawings in detail, the numeral I indicates ahollow frame orchute.

This chute may be connected to a hopperor any.

other suitable source of molding sand. The chute may itself be merely,the lower end. of a hopper. The molding sand is conducted down the chutel and is released through. the orifice 2 (Figure 4) at the lower end ofthe .chute.

The orifice 2 is closed by a primary gate 3. The primary gate 3 consistsof an arcuate plate 4 and a supporting arm 5 on each end of the plate.Each of the supporting arms 5 is shaped in the form of a segment of acircle. By means of a stud and nut. combination 6,. each ofv thesupporting arms 5 adjacent its apex, is vpivotally mounted to the chuteI. The plate 4-is shaped on a curve concentric with' the stud and nutcombination 6 whereby,,as it is operated,'it will trace a semi-circularpath. The endofthechute l is shaped to conform to the plate 4.

The primary gate 3 is actuatedby means of a. rod 1. The rod i is movedby any conventional mechanismsuch as. a handle, solenoid, hydrauliccylinder or similar device. The mechanism for moving the rod 'i'is notshown or described in greater detail. because it is .conventional andforms no part of this invention.

The chute I is provided with a depending lip 8 against which the primarygate 3 is closed. The lipflis preferablyone leg of an. angle element l 1designed .to support the edge of the hollow frame I against the impactof the primary gate 3 and to maintain a straight edge, and therebyeffect a good seal against the edge of the plate 4. The lip 8"alsoserves to prevent the material fromflowing into .the hereinafterdescribed secondary gate during the initial stages of the opening of theprimary gate. It will. be recognized that any other suitable, structuralshape may be substituted for the angle element ll.

Nested in the apex of the angle element H is a tube 9 extending thefulllength of the angle element. Through the tube 9 .extendsa rod It]. Theendsof the rod..l0.extend substantially beyond the, ends of both thetube 9 and the angle element II. The ends of. the rod In support thesecondary gate l5. This secondary gate 15 is. the dribble gate ordribble catcher. The secondary gate 15 consists of a shallow, V-shapedtrough l6 equipped at .each end withan end plate 11. Eachof the endplates I! has a hole for receiving.the rod Ill whereby the secondarygate 15 is. free to swing about therod I0, the rod l acting as a pivot.The, secondary gate I is held against movement axially'of the rod I 0 bymeans of the Ventionu cotter pins l8. The length of the secondary gatei5 is such that it will seat over the angle element, including the lip8, and the primary gate 3.

Closely adjacent the end of the rod ID, a stop or pin I9 is secured toone of the end plates H. The spacing of the pin l9 from the rod [0 isonly a short distance. A preferred center to center spacing betweenthese two elements has been found to be about three-quarters of an inch.Some departure from this preferred spacing may be made, but it must notbe increased such that the rapid opening of the secondary gate will beseriously delayed This will be subsequently explained under Operation.The pin !9, when the secondary gate is in closed position, issubstantially vertically aligned with the rod [0. Again-this is apreferred arrangement and some deviationfrom thisarrangement may be madewithout affecting theproper operation of my in- Mounted on the primarygate 3, adjacent the leading edgeZfloftheprimary gate 3, is an actuatorplate2 I. The actuator plate 2| is provided with an offset 22(Figuref'l), adjacent the primary gate 3,.whereby the main body. oftheactuator plate 2 I. will bealignedwith the pin [9.

The lower surface of the actuator plate. 2-! forms a curved, cam surface23;" This cam surface traces a curved pathv consisting of. a seg.-, mentof acircle, concentric withithev pivot point of the primary'gate 2, the.stud and nut combinae tion 6. The cam surface 23'is' designedto justclear the surface of. the rod lll'as the primary gate 3 is actuated. Bythis arrangement, the pin I9 willl'be forced into-substantiallyhorizontal,

alignment with the, rod I0, whenthe primary gate 3 is opened. It will berecognized that shouldit be desired to move thesecondary gate 15 througha still greater arc, the actuator plate 21 can be so designedthat. thecam surface 23 is loweredin relation to the rod W. The necessary minoradjustments in design can bereadilymade to avoid interference betweenthe actuator plate 21' and' the ends ofthe rod lU 'when thismodification is desired.

Adjacent therleading. edge 20' of' the primary" gate 3, there is anupwardly extending notch 24" in thecam surface 23."v The wall,25 of thenotch 24,.remote from the prima y. sate"3,is substantially perpendicularto the cam. surface 23. The depth and position of the notch is suchthat'when' both the primary gate3'and secondary'gate l5 are closed, thepin l9'will rest up in the notchin contact with, or substantially incontact with, the wal1.25. It will be understood that this open= ing inthe cam surface 23 need not be-a notchy'it may be a step with the wall25 constituting, the riser. Although the use of the pin l9 andactuatorplate 2 I" has been described'only' as existing on one side of the chuteI, it:wil1 be recognized that a duplicate structure canabe'providedonthe other side of the chute i.

Operation 1 The operation of my invention is relativelysimple. Whenthe-primary'gate 3 andth'e'secondarygate l5 are both closed '(Figure'2),a portion" of the secondary gate I5 is suspendedbeneaththe lip'8 and'theleadingyedge 'of-"the" primary gate 3'. A sufficient portion of" thetrough lfiiprojects. towardthe primarygate 3, beyond the edge of thelip. 8;.jthat it will inter cept any material running down the lip'8jSincethe wall of; the trough 'l 6;: directly beneath the lip-8;-isinclineddnwardly' toward the center of" the secondary gate, the materialwill be urged toward the center of the secondary gate [5. The materialwill be caused to work toward the center of the trough by the samevibration which initially causes the material to leak past the primarygate 3. The secondary gate acts primarily as a small, temporary, storagecompartment for the small quantities of material leaking past theprimary gate 3.

When the primary gate 3 is to be opened, an pward force is applied tothe rod 1, indicated by the arrow in Figure 3. This causes the primarygate 3 to move upwardly and away from the lip 8. The first shortmovement of the primary gate 3 forces the wall against th pin 19,causing the pin it to pivot about the rod it (Figure 3). Since the wall25 is substantially perpendicular to the cam surface 23, when theprimary gate 3 has moved only a very short distance in its openingstroke, the pin is has already been pivoted into a positionsubstantially in horizontal alignment with the rod Hi. This forces thesecondary gate completely out of the way of the stream of material beingreleased by the primary gate 3 and at the same time empties theaccumulated material from the secondary gate l5 (Figure 4). Since only aportion of the secondary gat [5 projects beyond the lip 8 into the pathof the material, the secondary gate i5 is entirely removed from the pathof this material, when the pin l9 has pivoted only a very short distance(Figure 3).

The cam surface 23 maintains the secondary gate in open or dischargeposition throughout the initial opening movement of said primary gate 3in its opening and closing operations (Figure 4). When the primary gate3 is being closed, the cam surface 23 and the wall 25 maintain thesecondary gate E5 in discharge position until the primary gate 3 issubstantially entirely closed. This delay of the closing of thesecondary gate I5, is as essential as the rapid removal of the secondarygate when the primary gate 3 is opened. Unless the closing of thesecondary gate is restrained until the flow of material from the chute lis stopped, it will become filled and will have no capacity for holdinthe material leaking past the closed primary gate.

It will be observed that minor variations may be made in the structureand arrangement used to carry out the principle of my invention whichwill not impair the rapid action of opening and closing the secondarygate and the timing of its operation in relation to the primary gate.Each of these changes will not affect the principle of my invention andare to be considered as included in the hereinafter appended claimsunless the language of these claims states specifically to the contrary.

I claim:

1. In gate construction for a device having a chute and a dischargeopening at the end of said chute, the combination comprising: a primarygate pivotally mounted on said chute; a secondary gate below saidprimary gate constituting a shallow trough and actuated by said primarygate; a plate at each end of said trough; means for pivotally mountingeach of said plates to said chute; a pin on one of said plates, said pinbeing above said pivotal mounting means when said secondary gate is inclosed position; an actuator plate mounted on said primary gate andprojecting away from said primary gate above said secondary gate in adirection opposite to the direction of movement of said primary gatewhen said primary gate is opened; said actuating plate having a camsurface tracing an are substantially concentric with said pivotalmounting for said primary gate; and a notch in said cam surface adjacentsaid primary gate for receiving said pin, said pin being immediatelyadjacent the wall of said notch remote from said primary gate when saidprimary gate is closed.

2. In gate construction for a device having a chute and a dischargeopening at the end of said chute, the combination comprisin a primarygate pivotally mounted on said chute; a secondary gate below saidprimary gate constituting a shallow trough and actuated by said primarygate; a plate at each end of said trough; a pivot for swingably mountingeach of said plates to said chute; a stop on one of said plates closelyadjacent said pivot, said stop being above said pivot when saidsecondary gate is in closed position; an actuator plate mounted on saidprimary gate and projecting away from said primary gate above saidsecondary gate opposite to the direction of movement of said primarygate when said 7 primary gate is opened; said actuating plate having acam surface directed toward said secondary gate and tracing an aresubstantially concentric with said pivotal mounting for said primarygate; and a notch in said cam surface closely adjacent said primary gatefor receiving said stop; the wall of said notch facing said primary gatebeing substantially perpendicular to said cam surface and in contactwith said stop when said primary gate is closed whereby the initialopenin movement of said primary gate will positively pivot saidsecondary gate through its entire arc of travel.

3. In gate construction for a device having a chute and a dischargeopening at the end of said chute, the combination comprising: a primarygate pivotally mounted on saidchute; a secondary gate below said primarygate constituting a shallow trough and actuated by said primary gate; aplate at each end of said trough; a pivot for swingably mounting each ofsaid plates to said chute; a pin on one of said plates closely adjacentsaid pivot, said pin being above said pivot when said secondary gate isin closed position; an actuator plate mounted on said primary gate andprojecting away from said primary gate above said secondary gateopposite to the direction of movement of said primary gate when saidprimary gate is opened; and said actuating plate having a cam surfacedirected toward said secondary gate and having an indented shoulderimmediately adjacent said primary gate; said cam surface tracin an arcsubstantially concentric with said pivotal mounting for said primarygate; the riser wall of said shoulder facing said primary gate beingsubstantially perpendicular to said cam surface; said pin restingagainst said riser wall when said primary gate and said secondary gatear each in closed position whereby the initial opening movement of saidprimary gate will positively pivot said secondary gate through itsentire arc of travel.

4. In a gate construction for a device having a chute and a dischargeopening at the end of said chute, the combination comprising: adepending lip on said chute along one side of said opening; a primarygate pivotally mounted on said chute for alternately opening and closingsaid opening; said primary gate in closed position engaging said lip; atrough shaped secondary gate pivotally mounted on said chute adjacentsaid primary gate andextending beneath said lip and saidprimamzgateg-whenizbothzsaid primary gate .andrri ffom'zsaidprlmarygatabeingmhan; acute Angle? said secondary gate: are:c1osed;'; a;pina on :said. seer to said cam surface:

ondany-gata abuve saidmivotalmounting ofisalidn secondary gate: to :said'nhutm an" actuatorv plate,- Referenoes--flited an, .the -fi1e: of thispatent: mounted Hon said: primary; gate" and :proj eating 5 UNITED;STATES PATENTS; mi-imm:said px'imanry gate alcovesaidasecondv;

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